Indicating instrument.



t Patented Mray i, |900. F. ROLLER.

INDICATING INSTRUMENT.

(Application med mr. 3o, 1899s,

(No Model.

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vnl/[(101111111111111111/In www enne UN IT an' STATES mzANKw. ROLLER, or NEW Youn,

PATENT' OFFICE.

INDICA'I'ING INSTRUMENT.

SPECIFICATION formingpart of Letters Patent No. 648,672, dated May 1,1900.

' Application filed March 30.1899. Serial No. r111.151. No modelJ To r/ :1f/1.0111J it may concern.-

llc it known that I, FRANK W.v ROLLER, a citizen of the United States,residing at New York, in the county of New York and State of New Yoil;,have invented certain new and useful Improvements in Indicating Instruments, of which the following is a full, clear, and exact specification. lhis invention relates to indicatinginstruments, and has particular reference to the means for illuminating the face-dial thereof.

'lhe object of the, invention is to providea simple and eiiicient means for lighting the dial with a dilused light.

In the instruments heretofore constructed having illuminated dials it has been suggested to locate behind a translucent dial-plate one or more lamps; but this has been found in practice to be objectionable, .because the light is not difliJ-sefl thoroughly and the -diused light 1is not evenly directed upon the plate.

' The various points upon the dial-plate eaunot, therefore, -be vreadily distinguished from all points of vision, According to my invention I propose to. obviate these difficulties by diusing the light and then casting the difl fused light upon the indicating-dial, thereby making it possible to read the scale from all points of vision.

The invention also com prehends otherl features of advantage, which will he mene particularly described hereinafter and pointed out in the appended claims.

In the accompanying drawings I have illustrated forms' which the linvention may take in practice, and in whichf' Figure 1 is a lfront view of an indicatingini strument embodying my invention. Fig. 2

is a sectional view of Fig. 1, and Figs. 3, 4, 5, and jare detail sectional views of modified formsof reflectors.

The instrument shown in the drawingsis' one used for the'measurement of electric eurrents, and the invention herein described will be found to be particularly applicable for use in connection with electric currents; but iti is to be understood that the invention may be applied t the face-plate of any'indicaiing `instrument.

In the drawings, 1 represents the'cas'ing, having an dpening 2 thereimthrough which the indicatingdial 3, having the usual calibrated employed, the plate 8 maybe transparent, en-

-the rays of light coming from the lamp. Un- .der practical conditions it will be found adscale, is adapted to be seen. The pointer or indicating-needle 4 is adapted to'move across the dial 3 to indicate the measure which the instrument is torecord, and nthis instance is shown as being mounted upon the spindle 5 and vibrated thereon by ythe influence of the current to be measured. A source of light 6, in this nstanceysh own as an incandescent lamp, is provided, and a reflector -7 is adapted to throw all the light therefrom through a translucent plate 8 upon a diffusing-plate i), from whence the rays of light are deilected toward the dial, ;3. Obviously theplate 8 is not an essential' feature of the invention and is shown herein for the reason that itis desirable to iuclose thel operating partsfof the indicating instrument in a closedicase. If

trely translucent, or, preferably,fopaque,

(Shownin Fig. 1.) The plate 9 may be of any suitable material or construction to diiuse vantageous to construct it of non-translueentfmaterial with a white diffusing-surface,I whereby the passage of the rays of light through the Plate will be prevented, and the the dial. In the drawings I have shown the plate 9 so located that it will also act as'a reiiector of the diffused light, casting thesame upon the indicating-dial. I prefer not to p01- `ish the4 plate 9, butto provide it with a nonor convexurface, as illustrated in Figs. 4.

and 5, or may be simply a straight surface at an angle tothe lamp, as illustrated i-n Fig. 3.

It may be noted that the reflector 7 may be dispensed with and the plate S'made either transparent or translucent. Either one ofthe reflectors Z or 9 must be adapted to diiuse therays of light. It is of course immaterial and provided with a translucent portion l0.

se light willbe more efectuallydirected against .whetlier the light be diffused bythe reflector' 7 or 9, and for the proper operation of the device at least one of the relectorsshould dit'- fuse the light.

In operation the rays of lightfro'm the lamp striking the diffusing-plate) 9 willbe diffused .l and the dilused'light reflected upon the indicating-dial, thus lighting'up evenly the entirefcliamber, formed bythedial 3, the top 1l been reflected in an undifused condition. It

has not beendiflused and the diffused light cast upon the dial. I therefore do vnot claim, broadly, the idea of reflecting light upon the dial in an undiffnsed condition.

By .my invention the dial may be read from any position,"and none of the characters upon the dial will be rendered obscure by reason of tbe reflection or refraction of undil'us'ed rays, such as heretofore rendered all illuminated dials' more or less'objectionable.

Having thus described my invention, I declare that what I claim as neng'and desire to secure by'Letters Patent, is- 4 l. In 'an indicating instrument, the cou1- bin ation ofan indieatingdial,a source of light, means for diffusing the rays of light from said source, and for directing said diffused light upon said dial, substantially as described.

2. lrjan indicating instrument, the combination ofan indicati11g-dial,a source of light, means for diffusing the rays of light from said source, and a plate adapted to direct the said diffused rays uponsaid indicating-dial, suhstautially as described.

3. in an indicating instrument, the combination of an indicating-diaLa source of light, and a plate adapted to diffuse the rays of light from said source, and direct said diffused light against said indicating-dial, substantially as described. l

4. In an indicating instrument, the combination ofan indicating-dial@ sou rce of light, a plate at the side of said dial, and adapted to ditfusethe rays of light from said source, and direct the same against said indicating-dial, substantially as described.

fln an indicating instrument, the combin ation of an indicating-diaLa source of light, and a non-translucent plate `having a white diffusing-surface upon which said light is directed, said plate being adapted to direct the said diffused light against said indicating.

dial, `substantially as described.

(i. In an indicating instrument, the combination ofan indicating-dial,a source oflight,

a plate having-an n'npolished white diffusingsurface upon which said light is directed, and means for directing the light l'rom said dil`-V fusing surface to the indicating-dial, substantially as described. 

